These questions are ones you might hear from a seven-year-old, and this book has the answers. Explore Solids and Liquids! with 25 Great Projects brings basic chemistry into the classroom or kitchen and makes it accessible for kids in grades two through four, and for anyone else who needs a refresher course in the different stages of matter.

Explore Solids and Liquids even goes beyond the three stages—solid, liquid, gas—many of us know from science classes past. Have you ever experienced non-Newtonian liquids? You probably have, even if you didn’t know it at the time! Non-Newtonian liquids behave differently in different situations. For example, when you try to punch your fist into a bowl of non-Newtonian liquid, it feels like a solid and your hand doesn’t get very far. If you slide your hand in gently, you can easily reach the bottom of the bowl.

This happens because there’s not enough space between those atoms to separate quickly and flow around your fist. When you move more slowly, however, those atoms have the time to rearrange themselves and behave like liquid around your hand.

Have you ever heard of oobleck? This is an easy non-Newtonian fluid to make at home or at school. Start with a cup of water in a rimmed cookie sheet and add about 1½ to 2 cups of cornstarch until it’s thick and gooey. Do some experiments with pennies, marbles, string, food coloring, and your hands!

You can watch a video of people playing with a pool of non-Newtonian liquid—they even try to ride a bike on the stuff!